RefrigDNA SenseNode — PINOUT & PCB NET SPEC  (Rev A1 / spec Rev C)
ESP32-S3 DevKitC-1. GPIO numbers are PROPOSED (TODO confirm vs board + signal integrity).

CH   SIGNAL              PART                 IF       ESP32-S3 PIN   NOTE
CH0  pipe temperature    TI TMP117            I2C      SDA=8 SCL=9    addr 0x48; sprung contact to pipe
CH1  vibration/accel     ADI ADXL355          I2C/SPI  SDA=8 SCL=9    +-8g; rigid to chassis for run-state
CH2  ultrasonic mic      Knowles SPU0414LRSH  ADC      GPIO4          38-42kHz; AFE + band-pass before ADC
CH3  ambient T/RH        SHT4x                I2C      SDA=8 SCL=9    addr 0x44; vent to room air
CH4  pressure            0-600psi transducer  ADC      GPIO5          amp to 0-3.3V; service-port
CH5  NDIR A2L (V2)       Dynament Axiom A2L    UART     RX=17 TX=18   service-port gas module; V2 unlock
DOOR contact (opt)       reed switch          GPIO     GPIO6          walk-in abuse
PWR  power               USB-C 5V / 12-24V DC  -        5V/3V3 rails   Rev C; LDO/buck to 3V3
NET  comms               on-chip              -        -              Wi-Fi 2.4GHz + BLE 5.0, MQTT/TLS

PCB NET LIST (for the EE turning this into a board):
- 3V3 rail: ESP32-S3, TMP117, ADXL355, SHT4x, ultrasonic AFE
- I2C bus: SDA(GPIO8), SCL(GPIO9), 4.7k pull-ups to 3V3; devices 0x48,0x44,ADXL355
- ADC: GPIO4<-ultrasonic AFE out; GPIO5<-pressure amp out
- UART2: GPIO17(RX)<-NDIR TX, GPIO18(TX)->NDIR RX (V2 populate)
- Power: USB-C VBUS or DC jack -> reverse-protection -> buck 3V3 -> ESP32-S3
- Test points: 3V3, GND, SDA, SCL, ULTRA_OUT, PRESS_OUT
- Mounting: 4x M3 to match CORE-05 standoff plate; outline = CORE-07 reserved footprint

STATUS: schematic-level net spec, ready for an EE to capture in KiCad. Not a routed board.